Method of blacking heated iron.



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METHOD or BLACKING HEATED IRON.

Specification of Letters Patent.

Patented Jan. 11, 1910.

N Drawing. Original application filed December 26, 1907, Serial No.408,188. Divided and'this application filed May. 11, 1908.

Serial No. 432,039.

408,188, filed December 26, 1907.

This invention relates to a method of treating iron which is intended tobe heated in use. Many compositions for stove blackings and polisheshave been made but most 15 of them involve, as the principal ingredient,

graphite which is applied mechanically and which is not in any wayunited to the iron but is merely rubbed on the surface of the same sothat it' will present a black surface for a limited period of time. Thegraphite is usually put up with a binder or the like which is decomposedby heat sothat after the blacking or dressing is applied it will becomeloosened and disappear in a short time after the stove or other articleon which it is used is heated to the ordinary temperatures to whichstoves and the like are subjected.

The principal purpose of this invention is to provide a method ofblacking or dressing WhlCh is so dependent on the ordinary heating of astove or the like that when the com osition is applied to the iron, itwill pro uce a coating intimately united with the surface of the ironwithout the interposition of any hinder or the like. In this way, asurface is secured which will only be more permanently fixed by heatingandcannot be removed in the ordinary use of the stove except by therepeated rubbing of -metal surfaces against the iron. In order toaccomplish this result, the iron is dressed with a metallic salt insolution either in combination with other substances or not, said ofsuch nature that a black metallic oxid preferably having a metallicluster will be fixed to the surface of the iron when the stove isheated. Preferably also a metallic ,.salt is used which is of such anature -that the desired result maybe secured in two ways; first simplyby decomposing the salt when the stove 1s heated to producethe black.

oxid; and second, by precipitating a metal from the salt upon itscontact with the iron even in a cold' state and leaving the metalintimately united with the surface of the iron and in such conditionthat when the metal is heated the black oxid will be formed and will beunited with the iron as in the other case. In all cases, the black oxidis in contact with the iron when in statu nascendz', so that it unitestherewith and ,thus produces a result not attained by simply coating theiron with the black oxid in suspension in a liquid, or mixed in a paste.

Asa specific example of a practicable way of carrying out the method,cupric hydroxid is dissolved, preferably in ammonia water, and appliedto the surface of the iron. It is well known that this hydroxidpossesses the property of losing its water when heated, even when underwater and being changed to black cupric oxid; consequently, if itisapplied to a hot stove the result will be the production of a surfaceof cupric oxid on the iron and as this surface is formed in a chemicalmanner while in contact with the iron WhlCh is in a heated condition,it, has

been found in practice that it is firmly united with the iron and canonly be removed by slow degrees in the ordinary use.

of a stove. Obviously, any further heating of the stovehas no effect onit after it is once fixed unless it be to morefirmly fix it in position.Consequently, the coating is exceedingly durable in practice and will bere-- moved only in the course of time by the constant attrition which itreceives by the use of utensils ordinarily employed on stoves.

Another important advantage of this method of carrying out the inventionis that the cupric oxid has a metallic luster and that it is composed,of a black amorphous powder so as to form a hard coating, which can beblackened over with ordinary forms of blacking so as to receive a highpolish therefrom. It is preferred also to place a black filler of anykind, as for example, tannate of iron, in the solution in any desiredpropor-' tion but preferably in a small quantity. This especially givesthe composition a body and serves to give a smoother surface to roughiron. It also by means of its color makes it look more like an ordinaryblacking and has no. deleterious effect onthe article when used for thepurpose for which it is intended. Another salt which can be used is thebasic copper carbonate. The cupric nitrate also may be used as it iseasily conwhich 'at high temperature settles together verted by heatinto black cupric oxid and as it is readily soluble in water andalcohol. When dissolved in water for this purpose,

it is preferred to first heat the solutionalmost to the boilin point andthen allow it to cool. It has een found in practice that while thisaction does not destroy the cupric nitrate, it prevents the formation ofgases in'the solution when the same is heated to moderate temperature,by being exposed to the sunlight, and thus makes a more stable articlefor commercial oses. This composition also is capable of precipitationof its copper when brought into contactwith the iron in a cold state,leaving the copper united with the surface of the iron in such form thatblack oxid will be produced when it is heated afterward. When thetannate of iron is usedthe nitrate should be slightly acid, and maycontain free nitric acid.

While I have described the use of copper salts for this purpose becauseof the nature of the copper and its black oxid, I am aware that certainother salts may be used equally well, as for instance,potassiumpermanganate. This is soluble in water at ordinary temperaturesand can be applied in the same manner as above described so as toproduce the black oxid of -manganese. The manganese dioxid or peroxidhas a metallic luster which renders it especially useful for thispurpose although a metallic luster is not absolutely necessary.Manganous nitrate also when heated to 150 degrees produces this oxid andcan be used in a similar way. All these solutions may be provided with afiller if desired, or in fact the manganese salts may be used inconnection with the copper salts. In that case, on account of thegreater body of the former they may be said to act in part as fillersfor the thinner copper salt solutions.

I am aware that the materials used and the method of carrying out theinvention may be varied by a skilled chemist without scope of theinventionv departing from the as expressed in the claims.

Having thus described my I claim is l. A method of dressing or blackingstoves which consists in applying to the iron a solution of a metallicsalt which is decomposed by heating to the ordinary temperatures of theheated stove I in contact with the iron thereof to produce a blackmetallic oxid, and heating the stove, whereby a durable coating orsurface of the black oxid will be left united and fixed to the surfaceof the iron.

-2.' A method of dressing or blacking iron which consists in applying tothe iron while cold, a solution of a metallic salt which is invention,what decomposed by contact with the iron, allow-a as for example,

and heatin tated meta will be oxidized and on the iron and then ing thesolution to dry a surface of heating the iron to produce black metallicoxid on the iron.

3. A method of dressing or blacking iron which consists in applying tothe iron, a solution of a metallic salt from which the iron willprecipitate the metallic base of said salt, the iron whereby saidprecipit e oxid will form a coating fixed to the surface of the iron. i

A method of blacking or dressing stoves and the like, consisting in aplying a mixture comprising a solution 0 a metallic salt which whenheated to the ordinary temperature of the heated stove in contacttherewith combines with the iron, and heating the stove to form adurable surface consisting of a black metallic oxid intimately andfixedly united to the iron.

5. A method :of

dressing or blacking iron which consists in applying to the ironasolution of a copper salt from which the iron will precipitate copper,heating the iron whereby said precipitated copper will be oxidized andthe oxid will form a coating fixed to the surface of the iron.

6. A method of dressing or blacking iron which-consists in applying tothe iron a. solution of a copper salt which is decomposed by heat toproduce black oxid of copper, and heating the iron whereby a coating ofthe black oxid will be left united to the surface of the iron.

7 A method of blacking or dressing iron which consists in applying tothe iron a so-- lution of a copper salt which is decomposed by heat toproduce black oxid of copper and which will precipitate copper bycontact with iron, and heating the iron whereby a coating of the blackoxid will be left united to the surface of the iron.

8. A method of blacking or dressing iron which consists in applying tothe iron a solution of cupric nitrate and heating the iron, so as toproduce a durable surface of black oxid of copper intimately united withthe iron;

9. A method of blacking or dressing iron which consists in heatingalmost to the boiling point a solution of cupric nitrate in water,allowing it to cool, applying it to the iron surface and heating theiron whereby asurface' of black oxid of copper is left intimately unitedwith the surface of the iron.

In testimony whereof I have hereunto set my hand, in the presence of twosubscribing witnesses.

GEORGE HIJOHNSON.

Witnesses:

ALBERT E. FAY, G. FORREST Wesson.

